This invention relates to rope rappelling, and more particularly to an effective controller device for enabling rappelling with control and safety.
A variety of devices have been proposed heretofore for controlling the descent of a person by rappelling. U.S. Pat. Nos. 4,019,609; 4,678,059; and 4,723,634 are typical of the prior art. All of these have no means of compensating for weight increase or decrease with corresponding increase or decrease in friction. They provide no ability to change friction when under load, and they provide relatively low friction and consequent difficulty of control for the operator. In U.S. Pat. No. 4,019,609 the controller can become derigged inadvertently when the rope is slackened, and it depends on carabiner gates in their weakest axis. In U.S. Pat. No. 4,678,059 the elements can shift, changing friction when the rope is slackened and then re-tensioned. The controller also may easily be reeved in a dangerous manner with the rope against the gate of one or more of the carabiners rather than the carabiner spine. In U.S. Pat. No. 4,723,634 the device must be disconnected from the harness in order to be reeved, and the rope can cross the device elements diagonally, creating twists in the rope (hockling) which can lead to spontaneous rope knotting that can jam a rappel device.